Compacted carbon black pellets

Abstract

This invention relates to carbon black pellets obtained by compaction of carbon black powder in the presence of auxiliary substances, which pellets, despite the compaction, surprisingly exhibit greater color intensity than the powders on which they are based.

What is claimed is:  
     
       1. Carbon black pellets, prepared from uncompacted carbon black powder, having a relative color intensity, based on the uncompacted carbon black powder, of greater than 100% which have been compacted two or more times with different compressive forces and/wherein the pellets comprise one or more binders and/or dispersants in a total quantity of between 0.1 to 25 wt. %. based on the weight of the pellets. 
     
     
       2. The pellets of  claim 1  wherein the pellets have an average particle size of 0.3 to 2 mm and a quotient of pycnometric density and bulk density between 3.0 and 10. 
     
     
       3. The pellets of  claim 1  wherein the binder comprises a liquid polyol, polyether, polyester, oil, water or an aqueous solution of a polymeric salt or molasses. 
     
     
       4. The pellets of  claim 1  wherein the dispersant comprises a lining sulfonate or a naphthalene/fornaldehyde condensation product. 
     
     
       5. A process for the production of carbon black pellets which comprises compacting carbon black two or more times with different compressive forces in the presence of an auxiliary substance in a total quantity of between 0.1 to 25 wt. %, based on the weight of the pellets and comminuting the compacted carbon black to pellets having an average particle size of 0.3 to 2 mm and a quotient of pycnometric density and bulk density between 3.0 and 10. 
     
     
       6. The process of  claim 5  comprising using compression forces of between 1 and 100 kN/cm. 
     
     
       7. The process of  claim 5  comprising performing the compaction by screws, rollers, die presses or extruders. 
     
     
       8. The process of  claim 5 , wherein the auxiliary, substance is a binder and/or dispersant used in a total quantity of 0.1 to 25% based on the weight of the pellet, and wherein the binder comprises a liquid polyol, polyether, polyester, oil, water or an aqueous solution of a polymeric salt or molasses. 
     
     
       9. The process of  claim 8 , wherein the dispersant comprises a lining sulfonate and a naphthalene/formaldehyde condensation product. 
     
     
       10. The process of  claim 5  comprising coating the resulting pellets with wax, polyether, polyolefin or polyvinyl alcohol. 
     
     
       11. The process of  claim 10  comprising adding a preservative and/or fragrance to the wax, polyether, polyolefin or polyvinyl alcohol.